RNP AR: Operational Approval

Honeywell's GoDirect RNP Consultancy meets with business jet operators that are interested in flying Required Navigation Performance – Authorization Required (RNP AR) approaches. The GoDirect team reviews regulatory guidance for operational approval with the client, and discusses the special requirements for flying the procedures. For operators looking to add RNP AR to their capabilities, here are some of the items discussed during those meetings.

Why Does the FAA Have Special Rules Around RNP AR? 

An RNP AR approach allows the procedure designer to place the aircraft closer to terrain or obstacles than other approach types permit, including traditional precision approaches. RNP AR procedures are designed with a narrow linear obstacle containment area only 2x the required RNP, with no secondary obstacle boundary as shown in Figure 1. RNP AR may also include curved flight paths (RF legs) in any segment of the procedure as shown in Figure 2. Because of this, the FAA and regulatory authorities worldwide have special certification requirements for the aircraft and crew. Information on FAA guidance is available in Advisory Circular AC 90-101A and AMC 20-26 (for EASA), but a call with GoDirect is less likely to induce sleep.

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Does a Flight Department Need Professional Assistance with the Application Process?

Because of the complexity of the application process in the US, the FAA created a consultancy program. Aircraft manufacturers and other OEMs became consultants, with Honeywell joining early in the program and focusing on the business jet market. The FAA recently ended the official consultancy program but recommends applicants work with existing RNP AR experts to gain operational approval. Honeywell's GoDirect RNP Consultancy will continue to assist business jet applicants with the process.

How Is an Aircraft’s RNP AR Capability Determined?

Before starting the RNP AR approval process, operators should make sure their aircraft is approved for RNP AR operations. This will be stated in the aircraft flight manual. Only the aircraft manufacturer can claim RNP AR capabilities, and if the aircraft is approved it will be clearly stated in the manual. 

Who Approves the RNP AR Application?

In the US, the application process starts and ends with the Principle Inspector (PI) through the local Flight Standards District Office (FSDO). RNP AR applications are concurrently reviewed by the Flight Operations Group (FOG) and Aircraft Certification Service (AIR) in Washington, DC. After the application is reviewed and found to meet all the eligibility requirements for RNP AR, a memo is generated and forwarded to the operator’s PI. After and on-site RNP AR validation test is conducted with the operator, the PI can issue LOA/OpsSpec C384 to conduct RNP AR operations..

What Goes Into the Application?

Application content requirements are determined by each country’s regulatory authority. For US operators, the application must address all requirements of AC 90-101A. Contents will include a flight department’s RNP AR operations pilot manuals, checklists, aircraft maintenance procedures, and navigation database handling procedures. Excerpts from aircraft flight manuals and logbooks showing RNP AR capabilities and system configuration must be included. RNP AR pilot training certificates and course syllabus are also required. Operators need to address how they will meet the RNP AR navigation database validation requirement (Honeywell can do that validation or provide tools to operators who want to attempt this task). Once approved, operators must make a monthly report to the FAA summarizing their RNP experience, until their PI advises it is no longer required.

Why Would an Operator Want to Go Through this Effort? 

RNP AR provides numerous benefits including greater access to terrain challenged airports and high volume airports with traffic flow constraints. RNP AR procedures also provide for a more stabilized approach though clearly defined lateral and vertical flight paths. Even greater benefits will be realized with the development of new RNP AR departure procedures..

Operators can learn more about RNP AR and the approval process by contacting GoDirect via email.

Honeywell Flight Technical Services supports pilots who use Honeywell products and services. They can be reached via email at FTS@Honeywell.com.